Paraview - ParaView is an open-source, multi-platform application designed to visualize data sets of size...
Gmsh - Gmsh is a 3D finite element grid generator with a build-in CAD engine and post-processor.
VisIt - VisIt is an Open Source, interactive, scalable, visualization, animation and analysis tool.
Altair - Visually Analyze Any Data at the Speed of Business
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
NETGEN - NETGEN is an automatic 3d tetrahedral mesh generator.